Bifurcator wrote:
Wow! maybe I should stick with 12mpx sensors then. That's a huge difference! I somehow don't think the extra 4mpx is worth losing 3 stops of DOF for!
Wow, were all your images that soft, like F/16 diffraction (equal to F/32 on FF) ?
alundeb wrote:
Wow, were all your images that soft, like F/16 diffraction (equal to F/32 on FF) ?
Pretty sure he's being "funny", while trying to convey the concept that one should match a composition's DOF to subject rather than to per-pixel acuity. e.g., in macro it's a constant battle to get enough of the subject into focus without destroying too much resolution via diffraction. It's nearly always more important to get all the critical bits into focus than it is to use every pixel, particularly when the intended output medium wouldn't show the drop in resolution anyway.
f8 is maximum for m4/3s since G1, usually you should rather stick to less (f5.6 - 6.3 is optimum, sometimes less, depends on lens). At least when you use native lens. Not sure about not-native as only non-native lens I tried was Voigtlaender 35mm f1.4.
Diffraction can have slightly higher effect on more mpix bodies, but diffraction unless its heavy is pretty much like gaussian blur, which means that bit of sharpening can help.
From lens point of view, it would be much better if most m4/3 lens were designed as f1,0 - f2,0 as they would reach peak performance around f4 or sooner.
There are some examples of this, usually made by Voigtlaender. Their 25mm f0.95 is pretty sharp at f4.
And about shallow DOF, actually no issue with m4/3s, just use these..
Voigtlaender 17mm f0.95 (fringes a bit)
Voigtlaender 25mm f0.95
Voigtlaender 35mm f1.2 V2
Voigtlaender 50mm f1.1 (or alternative f1.2 any MF lens in similar focal length)
Further, you can get some nicely fast telephotos, try for example Contax 100mm f2, bokeh is still pleasant even on m4/3s and you have effectively 200mm f4 with which you will have more issues to stay within DOF, than not having enough DOF.
Shallow DOF isnt issue on m4/3s, just its bit pricey. Btw. Leica 50mm f0.95 can give you 100mm f1.9 equiv.. which doesnt even have equiv in full-frame world. SLR Magic lens too.. (for much less money).
Maybe somebody can help me out here but when I look to the resolution charts in the lens tests on most of the lens review sites, I can only seen the diffraction being a real issue above f8 in m4/3 not f4 or f5.6. Surprisingly, that matches my experience with these cameras.
I think that diffraction issues are blown way out of proportion for these and other cameras (D800, D7000, sonys, Canons or you name it).
I think that it is one of those trends that one can find on photo forums. It is the same than the people who used the D7000 without major problems and all of a sudden started feeling bewildered with how difficult is too take sharp images with the D800.
Bifurcator wrote:
Wow! maybe I should stick with 12mpx sensors then. That's a huge difference! I somehow don't think the extra 4mpx is worth losing 3 stops of DOF for!
You won't lose 3 stops of DOF. In fact, in no way will your effective resolution be worse with the 16MP sensor as with a 12MP sensor. Even if, at the pixel level, diffraction is limited, as an effect of the overall image, it will be the same or better resolution on the higher resolution sensor as it would be on a 12 MP sensor.
Also, anyone saying that images get soft at f/8 is full of crap. Sorry. Is there maybe a small dropoff on some lenses from f/5.6 to f/8? Sure...depends on the lens. But that's the case with many lenses, where the peak sharpness is at f/4-f/5.6 (not necessarily due to diffraction). I've seen a little softening on shots at f/11 (though still perfectly usable and fine...you'd never notice unless you were comparing directly.) and a little more at f/16. Beyond f/16 is where sharpness really drops off. Still, this is the same as shooting at f/32 on full frame, so it's not unexpected.
BTW...I have never seen this level of nitpicking in this forum before. When did the alt people become so obsessed with technical minutiae...it's starting to feel like DPReview in this thread.
Mescalamba wrote:
Btw. Leica 50mm f0.95 can give you 100mm f1.9 equiv.. which doesnt even have equiv in full-frame world. SLR Magic lens too.. (for much less money).
Agree with pretty much everything you have said but there are plenty of relatively fast FF 100mm lenses out there such as the older but very good Minolta AF 100/2, Canon 100/2, Nikkor 105 1.8 and F2 DC, Olympus 100/2 and so on.
Diffraction effects are an objective technical fact and do become visible at the F-stops mentioned above with each format. Whether or not it matters to one person or another, or is necessary to accept to some degree for a better photograph is a subjective issue. It's a gradual fall off in any case. If it's not observed it's due to a limitation of either the lens (which is why it might show up with one lens after F4 but another lens after F8! with m43), sensor or user technique.
Javier Munoz wrote:
Maybe somebody can help me out here but when I look to the resolution charts in the lens tests on most of the lens review sites, I can only seen the diffraction being a real issue above f8 in m4/3 not f4 or f5.6. Surprisingly, that matches my experience with these cameras.
That is my essentially experience as well. For landscape I typically set the aperture at F/6.3 and leave it there, best center sharpness and edge sharpness for the zooms. For some lenses F/8 is a trade off between slight degradation in the center for a improvement in the extreme corners/edges. For a few primes that are extremely sharp in the center, on a 16MP body there is at least a measurable peak at about F/5.6 for MTF50. Very gentle roll-off towards F/8. Visible difference? Not in my experience, but I'm sure at 100%, side by side with an extreme contrast curve someone could identify the F/8 vs. F/6.3 shot.
Many of the extreme "diffraction" debates are based on naive calculations of the first Airy null combined with the pixel pitch and completely neglect the AA filter, Bayer CFA and demosaic algorithms (all of which involve both filtering and sharpening). It is these folks that know just enough math and physics to get themselves in trouble that come up with "diffraction" limits of F/4 and what not for m43 and F/8 for FF. Many folks often also seem to forget that once you get to DoF limited shooting (i.e. you are using smaller apertures to expand the DoF) that format is entirely irrelevant - the achievable DoF and diffraction effects are identical at all format sizes. The only exception is in macro shooting where there is a trade off difference.
This thread is getting a little crazy and pointless to me at this point. I'm not even particularly interested in fast zooms myself - on any format!
Someone post some sample photos - you know, in summer of 2013 when we can actually get the lens from Panasonic
Javier Munoz wrote:
THere are reviews and/or samples from the lens in slgear and ephotozine. I think that there are other sites with reviews but I saw those 2 recently
Yes, I saw those, and looking pretty darn good. I was being tongue-in-cheek
Bifurcator wrote:
Wow! maybe I should stick with 12mpx sensors then. That's a huge difference! I somehow don't think the extra 4mpx is worth losing 3 stops of DOF for!
i think your just not looking carefully enough. on my old 10mp 4/3 sensor i could barely notice diffraction between f/5.6 and f/8 and i really noticed it between f/8 and f/11. really though, seeing diffraction is a good thing. it means you are getting the most out of your lens.
The Panasonic 12-35mm ƒ/2.8 offers very sharp results, consistent across all focal lengths. The lens offers almost tack-sharp performance when used wide open at ƒ/2.8, with only a bit of softness in the extreme corners; stopping down to ƒ/4 provides solid edge-to-edge sharpness. In fact, ƒ/4 seems to be the optimal aperture for this lens, as results actually degrade very slightly when the lens is stopped down further than that. This is all very relative, though - results are still extremely sharp from ƒ/5.6 through to ƒ/11, with diffraction limiting only becoming practically visible at ƒ/16. At ƒ/22, we noted some light softness across the frame.
carstenw wrote:
Well yes, but do re-read the sentence bolded
I don't need to re-read it. One remark is objective and based on measurements and the other is completely subjective and will differ depending upon who is looking at the results. I'm guessing if they say something as outrageous as that (F16 on m43), pretty much any of us here would disagree when looking at the results. "Practically visible" is not a very specific, objective term.
Yes, but as clearly demonstrated numerous times a MTF50 number is not a reliable direct metric of lens "sharpness" or "acuity" or even of "diffraction". So drawing conclusions about diffraction based on what aperture there is a MTF50 peak is giving one a false sense of rigor despite the appearance of being "objective".
If you haven't seen it before, a good outline of the pitfalls associated with over analyzing and drawing direct conclusions from MTF plots:
P.S. I do agree that by F16 on m43 I can see effects at 100% without doing anything extreme to the image, and I agree about your conclusions regarding the subjectivity of such a statement. I'm just saying don't fool yourself with pretty plots and numbers, they appear to be rigorous but in reality the are not.
All I know is that I saw the difference with real images using the Panasonic 14 on the GH2 going beyond 5.6 and clearly see the difference on FF 24MP's going beyond F8 (with a great lens, it's actually pretty noticeable beyond 5.6 in my experience), no charts or MTF's required. Again though, I'm certainly not saying a lens can't or shouldn't be used beyond where diffraction effects become noticeable. It's just nice to know the capabilities and limitations of the tools. With FF high MP, I never shoot beyond around F8 unless I really need the dof since I know I'm throwing away a little resolution when I do so. Hard to imagine why the smaller pixels of m43 would be more resistant to showing diffraction effects.
agreed, you don't need to do anything "extreme" to an image to see diffraction past f/5.6 on µ4/3. just take the same shot at f/5.6 and f/8 (with a good lens) and switch back and forth between them at 100%. it pretty obvious even if it isn't bad enough to ruin a shot.
All I know is that I saw the difference with real images using the Panasonic 14 on the GH2 going beyond 5.6 and clearly see the difference on FF 24MP's going beyond F8 (with a great lens, it's actually pretty noticeable beyond 5.6 in my experience), no charts or MTF's required.
Well, I'd consider that a valid evaluation then. I guess it has a lot to do with what part of the frame you are looking at as well - as a landscape shooter I'm often staring at the edges where aberrations are worse. So my experience is probably different from yours - certainly in the center you would notice diffraction earlier. I'm sure with great glass on a 24+MP full frame it is even more noticeable (I have managed to avoid the siren song of such things so far).
agreed, you don't need to do anything "extreme" to an image to see diffraction past f/5.6 on µ4/3. just take the same shot at f/5.6 and f/8 (with a good lens) and switch back and forth between them at 100%. it pretty obvious even if it isn't bad enough to ruin a shot.
You're right, I checked and it is noticeable at 100% with a standard contrast curve on a sharp prime at the center of the image. Less obvious with the zooms, but still noticeable (which is why I usually shoot zooms at F/6.3 - sweet spot for corners without getting to the beginnings of degradation in the center that are noticeable at F/8). I don't use my 45/1.8 for landscapes too often, but I've been shooting it at F/5.6 as it does get a bit more sharp in the center with good edges.
That's a huge difference! I somehow don't think the extra 4mpx is worth losing 3 stops of DOF for!
